WO 2009/103736 describes a vacuum infusion or vacuum assisted resin transfer moulding process used for moulding fibre composite mouldings. In such a process uniformly distributed fibres are layered in a first mould part, the fibres being rovings, i.e. bundles of fibre bands, bands of rovings or mats, which are either felt mats made of individual fibres or woven mats made of fibre rovings. A second mould part, which is often made of a resilient vacuum bag, is subsequently placed on top of the fibre material. By generating a vacuum in the mould cavity between the inner side of the first mould part and the vacuum bag, the liquid polymer can be drawn in and fill the mould cavity with the fibre material contained in the mould. So-called distribution layers or distribution tubes (in the following also called inlet channels) are used between the vacuum bag and the fibre material in order to obtain as sound and efficient distribution of polymer as possible. In most cases the polymer applied is polyester, vinyl ester or epoxy, and the fibre reinforcement is most often based on glass fibres or carbon fibres, but may also be plastic fibres, plant fibres or metal fibres.
During the process of filling the mould, a vacuum, i.e. an under-pressure or negative pressure, is generated via vacuum openings in the mould cavity, whereby the mixed epoxy is drawn into the mould cavity via the inlet channels in order to fill said mould cavity. From the inlet channels the resin disperses in all directions in the mould cavity due to the negative pressure as a flow front moves towards the vacuum channels.
Therefore, the apparatus further comprises a flow sensor for measuring an airflow arranged so as to be able to measure the airflow through the interior of the sealed container. The sealed container is used as an overflow container for collecting excess resin from the filling process.
After casting, these overflow containers will be emptied. In order to avoid any hazardous situations during this step, it is demanded to wait until the mixed resin in the overflow container is solidified before discarding the hardened resin. One option is to wait a long time or to heat the resin mixture for enhancing the curing rate and, thus, speeding up the solidification process.